Process and mold for making cast metal boilers for furnaces or other heating units



-M. PROCESS AND MOLD FOR MAKING CAST METAL BOILERS Nov. 17, 1942. 1.. DOELMAN FOR FURNACES OR OTHER HEATING UNITS Filed June 30, 1941 Patented Nov. 17, 1942 UNITED STATS PROCESS AND MOLD FOR MAKING CAST METAL BOILERS FOR FURNACES OR OTHER HEATING UNITS Application June 30, 1941, Serial No. 400,435 In Canada November 18, 1949 6 Claims.

This invention relates to cast metal boilers for furnaces or other heating units.

The common practice is to cast boilers in sections which are assembled either at the factory or when the furnace is installed. While this construction has certain advantages, it requires a considerable amount of machining to make the sections fit tightly; it necessitates considerable unnecessary material and weight; and there may be leakage between the sections. cast boiler would overcome all these objections, and the object of my invention is to produce such a boiler and to devise a suitable process and molds for doing so.

The invention is more particularly described and is illustrated, by way of example, in the accompanying drawing in which Figure 1 is a horizontal section of the mold on the line II in Figure 2;

Figure 2 is a vertical longitudinal section of the mold on the line 2-2 in Figure 1;

Figure 3 is a vertical cross-section of the mold 011 the line 3-3 in Figure 1; and

Figure 4 is a perspective View, partly broken away, showing the completed boiler, standing on its rear end to correspond with the position in which it is molded.

In the drawing corresponding numbers in the different figures refer to corresponding parts.

The mold is made out of suitable molding material, such as sand mixed with an oil binder which vaporizes during the molding operation permitting the sand to crumble so that it may readily be removed from the interior spaces. The mold is builtup by units or blocks of molding material suitably arranged and spaced to form the Walls of the 'boiler casing and flues and of the water spaces between the walls of the casing and the walls of the flue. It will be ob served that additionally, there is provided a fuel opening and an open-sided space forming the upper part of the fire-box, sometimes called the dome of the furnace.

The base I of the mold is formed of a sheet of molding material upon which the rest of the mold is built up. Placed on the base I is 2. rectangular hollow mold section 2 which extends around the whole periphery of the base I. Chaplets 3 are placed on the base I for supporting the core member 4 which fits within the recess formed by the mold section 2. It will be observed that the core member 4 is provided with aseries of apertures to form flue openings and that it is spaced from the base member I and from the mold section 2 to form spaces for re- A single unit ceiving molten metal to form the back and ends of the casing of the boiler. The core member t is provided with projections 4* which bear against the base I to form openings in the walls of the casing of the boiler to form water inlets and outlets in the completed boiler. The core member 4 is hollowed out for more than half of its length, and another core member 5 is placed in said hollow and supported by chaplets 6. The space between the core members. 4 and 5 forms the inner wall of the lower part of the boiler and of the entrance to the lower flue.

Placed on top of the mold section 2 are a plurality of mold members I which rest on the mold members 4 and 5. It will be noted that there is a U-shaped opening in the mold members 'I to receive the various core members forming the fines and water jacket.

Placed on top of the core members 4 and 5 and occupying the rectangular space provided by the mold members I are a plurality of core members 3 of a thickness equal to the thickness of the mold members 1, spaced from the mold members 1 to provide a space for receiving molten metal to form the walls of the coating and having rectangular apertures therein for forming the flues of the boiler. The lower of the core members, 8 is reduced in thickness at one end to provide a space between it and the core member 5 to form the wall of the space leading from the fire-box of the boiler to the lower flue. On top of the mold members I is a rectangular mold member 9 of the same shape as the lower rectangular mold member 2. Placed within the rectangular mold section 9 and resting on the mold member I as shown in the upper right hand of Figure 2 is a mold member Iil, and placed in top of the upper core member 8 is another core member II which is under-cut at the right-hand end in Figure 2 to receive the mold member III. The members It] and II are spaced to provide space for molten metal to form part of the inner wall of the boiler and the under-cut end of the core member II may be supported by chaplets I2. Placed on top of the mold section I is a rectangular top mold member i3 corresponding to the base I.

As previously stated, the core members are provided with holes for forming the flues. In

the drawing two rows of flues each comprising three fines are shown. The core member I4 fits into'the holes provided for the first or upper row of flues, with a space extending around it to receive the molten metal to form the two walls.

55 The cores I5 are placed in the holes provided for the second or lower row of flues and are similarly spaced to provide space for the molten metal to form the walls of the flues. It will be observed that the lower end of the core [5 rests on the core member 5 and the upper end is in contact with the upper mold member 13 so that in the completed boiler the flue will extend through the wall of the casing of the boiler. The core member 5 may be formed with a print or slight recess in which the core member l5 could seat to give it a definite lateral location. This would also apply to any of the cores which contact the back or front exterior core or mold members. The core l4 rests on the base I and engages the upper mold member l3, so that the flues when completed will extend through the walls of the casing of the boiler at both ends. Although two rows of three comparatively large rectangular flues are shown, it will be understood that cylindrical flues may be formed. Further,

one of the advantages of the invention is that flues may be made smaller and spaced more efficiently than is possible by previously known methods.

To form a fuel opening into the fire-box of the completed boiler, a core member is is placed on top of the core member l and extends through a hole or opening in the core member H, being spaced therefrom to provide a passage for the molten metal to form the wall of the fuel opening, and engaging the upper mold member l3 so that the opening will extend right through the casing of the boiler.

For pouring the molten metal, a hub i3 is formed on the mold member l3 and has a funnelshaped opening I! extending therethrough communicating with a cylindrical vertical hole or opening I! extending right through the core members [0, ll, and 4. Radiating from this opening and formed in the upper surfaces of the various core members 1 are runners I8 which extend to the spaces provided for forming the inside walls of the fire-box, and from those spaces to the spaces for forming the outside walls of the casing, and to the spaces provided for forming the walls of the flues. Continuations I8 of the runners l8 extend between the spaces provided for the walls of the lower row of th flues to the space's'provided for forming the upper row of flues and from the spaces provided for forming the upper row of flues to the spaces provided for forming the walls of the casing.

After the molten metal has been poured the molding material is removed from around the outside and inside of the casing and from the inside of the flues. The mold material which is in the space between the walls of the casing and the walls of the flue has been dried out by the heat of the molding operation and is quite fluid, and can be shaken out of the openings formed by the projections 4 on the mold member 4 and 8 on one of the core members 8 or by any other openings through the casing which may have been formed in the molding process or by tapping for connecting water pipes thereto.

The rods or strips of material left in the pouring opening I! and the mold I! and in the runners extending from the opening I! to the inside walls of the casing will be broken away in the usual manner. However, the material which hardens in the runners extending between adjacent walls of the casing or between th walls of the casing and the walls of the fiues, or between adjacent fiues, will not be removed, but will remain in that position providing stays (see Figure 4) for strengthening and reinforcing the walls of the casing of the boiler and the flues.

The core members will, of course, require to be suitably vented to permit the gas generated by the burning of the core material to escape from core to core and to the atmosphere. For this purpose a small opening will be provided in each core member in register with a similar opening in the adjacent members and communicating with the exterior of the mold. Since this is common practice and the opening will be placed in such locations as experience indicates will be necessary, they are not shown in the drawing.

It will of course be obviou that the completed boiler will be mounted on a base and provided with the usual external jacket, water connection, smoke pipe, etc., which need not be described here.

While the invention has been described in some detail, the description is by way of example only, and applicant does not desire to be limited to the specific construction shown except as specified in the annexed claims.

What I claim as my invention is:

1. A process of molding boilers having a casing containing a water jacket, which consists in forming the mold of superimposed blocks of suitable molding material having a gate and grooves in the surfaces of the blocks forming runners to carry the molten metal to the space provided for forming the walls of the casing, said runners extending between different parts of the casing wall space, pouring the metal, cooling it, and removing the molding material leaving the hardened metal in th runners between the walls of the casing to form internal supporting stays between said walls.

2. The process of molding boilers, having a casing, a flue, and a water jacket surrounding the flue, which consists in forming the mold of superimposed blocks suitable molding material and core material having a gate and grooves formed in the surfaces of the blocks forming runners to carry the molten metal to the space provided for forming the walls of the casing and the flue, said runners extending between the easing wall space and the flue wall space, pouring the metal, cooling it, and removing the molding material leaving the hardened metal in the runners between the walls of the casing and the walls of the flue to form internal supporting stays between the flue and casing walls.

3. A mold for making boilers, comprising superimposed blocks of molding material and core material built up and arranged with a space to form a casing having spaced apart walls forming a water jacket therebetween in the completed boiler, a vertical gate, and grooves in the surfaces of the blocks forming transverse runners connecting the gate with the space for forming one of the walls of the casing and through the core material which forms the water jacket to the space which forms another wall of the boiler, whereby when the molten material in the runners is hardened it will form internal stays for supporting and strengthening the walls of the casing.

4. A mold for making boilers, comprising superimposed blocks of molding material and core material built up and arranged with spaces to form a casing and a flue extending between and spaced from the casing, a vertical gate, and grooves in the surfaces of the blocks forming a plurality of transverse runners connecting the gate with the spaces forming the walls of the flue and the walls of the casing, said runners extending between the casing space and the flue space, whereby when the molten material in the runners is hardened it will form internal stays for supporting and strengthening the walls of the flue and easing.

5. A mold for making boilers, having a casing, flues, a water jacket and a fire-box, comprising superimposed blocks of molding and core material built up and spaced to form walls for the boiler casing and walls for flues extending transversely of and spaced from the walls of the casing, the molding material being provided with a vertical gate extending through blocks of molding material forming the fire-box, and grooves in the surfaces of the blocks forming the fire-box and the water jacket, said grooves radiating from the gate and extending to and between the spaces provided in the mold for forming the walls of the casing and the flues.

6. A mold for making boilers, having a casing, flues, and a water jacket, comprising superimposed blocks of core material built up and spaced to form Walls for the boiler casing and walls for flues extending transversely of and spaced from the walls of the casing, the molding material being provided with a vertical gate extending through blocks of molding material, and grooves in the surfaces of the blocks, said grooves forming runners and extending from the gate to and between the spaces provided in the mold for forming the walls of the casing and the flues, whereby when the molten material in the runners is hardened it will form stays for supporting and strengthening the walls of the flues and the casing.

MYRON L. DOELMAN. 

